Transcript Level I Review

Level 1 Review
Level I Review
Avalanche Types and Characteristics
1) What are the main characteristics of a slab
avalanche?
a)
Large
b)
Well defined bed surface
c)
Dry snow
d)
Wet snow
e)
Crown (Fracture Line)
f) Tear drop shape
g)
Flanks
h)
Cohesive snow
i)
Un-cohesive snow
j)
Easier to predict
k)
Harder to predict
Level I Review
2) What are the main characteristics of a loosesnow avalanche?
a)
Large
b)
Well defined bed surface
c)
Dry snow
d)
Wet snow
e)
Crown (Fracture Line)
f) Tear drop shape
g)
Flanks
h)
Cohesive snow
i)
Noncohesive snow
j)
Easier to predict
k)
Harder to predict
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3) An avalanche with a large cloud of snow
suspended in the air is called a “powder avalanche.”
True False
4) Describe the destructive potential of a Class 2
Avalanche using the Canadian classification system.
5) Describe the size of a Size 2 avalanche using the
American classification system.
Level I Review
Avalanche Terrain
6) What are the two main terrain factors that influence
where avalanches might start?
7) Some common trigger points are:
a) Convex areas
b) Shallow snow
c) Scattered trees or rocks
d) Below cornices
8) What are three signs that avalanches have run in the
past?
9) What are terrain traps? Give two examples.
Level I Review
Creation and Metamorphism of the Mountain Snowpack
10) Atmospheric snow falls from the sky in various shapes
and sizes. True False
11) Differing snow types and weather conditions cause the
snowpack to form in layers. True False
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12) Circle “M” to indicate a maritime climate characteristic
and “C” to indicate a continental climate characteristic:
M
M
M
M
M
M
M
C
C
C
C
C
C
C
High precipitation rates
Strong pre-storm winds
Cold temperatures
Shallow variable snowpack
Strong, uniform, snowpack with mostly rounded grains
Avalanches often occur without significant storms
Avalanche danger rises quickly and falls quickly
Level I Review
13) The main “direct weather” factors that cause layers at
or near the snowpack surface to change characteristics
are:
a) Wind
b) Humidity
c) Surface hoar
d) Sun
e) Riming
f) Rain
g) Temperature
Level I Review
14) Once layers are buried more deeply, weather affects
them indirectly and faceting or rounding are the main types
of metamorphism. Circle “F” for faceting or “R” for rounding
to indicate which process is more likely to occur due to the
following factors:
F
F
F
F
R
R
R
R
Shallow snowpack
Warm air temperatures
Deep snowpack
Cold air temperatures
Level I Review
Avalanche Danger and Danger Factors
15) Three conditions are required for avalanche
danger to exist. They are:
a)
b)
c)
d)
e)
f)
Unstable snow
High altitudes
Poor weather
Avalanche terrain
People, equipment, or facilities
Warm temperatures
16) List the five avalanche danger rating categories.
Level I Review
17) Factors that influence avalanche danger or indicate that
danger may exist are recorded in three data classes. They
are weather, snowpack, and avalanche activity. In each of
these data classes there are a number of information
categories. Choosing from the list below right, place the
information categories under the correct data class heading
on the left.
Data Class
Weather
Snowpack
Avalanche Activity
Information Categories
Precipitation
Layers
What triggers?
Snow cover
Solar radiation
How do they look?
Bonding
When did they happen?
Wind
Temperature
Instability signs
Level I Review
18) We make observations in each information category to help make decisions
about avalanche danger. When we see a critical value we often call it a “red flag”.
List two important observations we make in each of the following information
categories and red flag values that would indicate avalanche danger. An example
is provided to get you started:
Information Category
Precipitation
Observations
Intensity
Accumulation
Red Flags
> 3 cm/hour
> 30 cm in 12 hours